AISI 403 (S40300) Stainless Steel
AISI 403 stainless steel is a martensitic stainless steel formulated for primary forming into wrought products. 403 is the AISI designation for this material. S40300 is the UNS number. Additionally, the British Standard (BS) designation is 403S17.
This material is well established: the Further Reading section below cites a number of published standards, and that list is not necessarily exhaustive.
It has the lowest base cost and a moderately low embodied energy among wrought martensitic stainless steels.
The properties of AISI 403 stainless steel include two common variations. This page shows summary ranges across both of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare AISI 403 stainless steel to: wrought martensitic stainless steels (top), all iron alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Brinell Hardness
190 to 240
Elastic (Young's, Tensile) Modulus
190 GPa 28 x 106 psi
Elongation at Break
16 to 25 %
Fatigue Strength
200 to 340 MPa 29 to 50 x 103 psi
Poisson's Ratio
0.28
Reduction in Area
47 to 50 %
Rockwell B Hardness
83
Shear Modulus
76 GPa 11 x 106 psi
Shear Strength
340 to 480 MPa 49 to 70 x 103 psi
Tensile Strength: Ultimate (UTS)
530 to 780 MPa 77 to 110 x 103 psi
Tensile Strength: Yield (Proof)
280 to 570 MPa 41 to 83 x 103 psi
Thermal Properties
Latent Heat of Fusion
270 J/g
Maximum Temperature: Corrosion
390 °C 730 °F
Maximum Temperature: Mechanical
740 °C 1360 °F
Melting Completion (Liquidus)
1450 °C 2640 °F
Melting Onset (Solidus)
1400 °C 2560 °F
Specific Heat Capacity
480 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
28 W/m-K 16 BTU/h-ft-°F
Thermal Expansion
9.9 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
2.9 % IACS
Electrical Conductivity: Equal Weight (Specific)
3.3 % IACS
Otherwise Unclassified Properties
Base Metal Price
6.5 % relative
Density
7.8 g/cm3 480 lb/ft3
Embodied Carbon
1.9 kg CO2/kg material
Embodied Energy
27 MJ/kg 11 x 103 BTU/lb
Embodied Water
99 L/kg 12 gal/lb
Common Calculations
PREN (Pitting Resistance)
12
Resilience: Ultimate (Unit Rupture Work)
110 to 120 MJ/m3
Resilience: Unit (Modulus of Resilience)
210 to 840 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
19 to 28 points
Strength to Weight: Bending
19 to 24 points
Thermal Diffusivity
7.6 mm2/s
Thermal Shock Resistance
20 to 29 points
Alloy Composition
Among wrought stainless steels, the composition of AISI 403 stainless steel is notable for containing comparatively high amounts of chromium (Cr) and manganese (Mn). Chromium is the defining alloying element of stainless steel. Higher chromium content imparts additional corrosion resistance. Manganese is used to improve ductility at elevated temperatures. It also permits a higher nitrogen content than would otherwise be possible.
| Fe | 84.7 to 88.5 | |
| Cr | 11.5 to 13 | |
| Mn | 0 to 1.0 | |
| Ni | 0 to 0.6 | |
| Si | 0 to 0.5 | |
| C | 0 to 0.15 | |
| P | 0 to 0.040 | |
| S | 0 to 0.030 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM A176: Standard Specification for Stainless and Heat-Resisting Chromium Steel Plate, Sheet, and Strip
ASTM A473: Standard Specification for Stainless Steel Forgings
ASTM A479: Standard Specification for Stainless Steel Bars and Shapes for Use in Boilers and Other Pressure Vessels
ASTM A276: Standard Specification for Stainless Steel Bars and Shapes
Creep-Resistant Steels, Fujio Abe et al. (editors), 2008
ASTM A240: Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
Advanced Materials in Automotive Engineering, Jason Rowe (editor), 2012
Welding Metallurgy of Stainless Steels, Erich Folkhard et al., 2012
ASTM A959: Standard Guide for Specifying Harmonized Standard Grade Compositions for Wrought Stainless Steels
Pressure Vessels: External Pressure Technology, 2nd ed., Carl T. F. Ross, 2011